Wired with >8 mb/s. While it's stable it's incredibly slow. I guess there are people out there with worse, but after having wired 100 mb/s this feels like the stone age and downloading anything but mini albums or pictures takes a long time. Playing WoW works just fine, though. As long as you have a stable connection you'll be good. Speaking from experience, wireless is not very stable.

I play wireless. No idea what the speed is...haven't paid attention, but I get about 50 - 70ms latency. I did find I had to change the channel on the router a few times to find one not being overly used by everyone else. Symptoms of that is extreme lag and disconnects as well as trouble connecting.

I play wirelessly. My only issues with connections have been when the cable modem and/or the router was acting up, or there was an issue somewhere between Blizzard's servers and my modem. I usually see 30-50 ms latency on both.

Edit: I did mess with the channel on my router to try to escape overlap interference, but ultimately found that the default channel worked the best by far, anyway. Speed's never been an issue; I believe I usually am between 3mb and 16mb, depending on whether my spouse is streaming video or not.